I found solution form my problem. Trivial.
There was no bug, like I suspected.
The log file located at /var/log/rsync.log was huge above 100 MB. I couldn't view it via Diagnostics/Systemlogs/Rsync Jobs - "Connection Failure" so I moved it somewhere else and now I can synchronize data without special options f.e. -e "ssh -p 44225" on any ports without any glitches.